660cc to be safe.its only 400 bones.i was gonna get 720cc,but that might be over kill for stock turbo

 

Thanks again to all. This is just what I needed. I think I will stay stock for now and use that money for a good tune.

TurboTrix for the custome tune coming up in LA would you be able to install the cams just before or anytime before my tune? If so please pm with with details. Thanks

 

I don't think 720's are overkill. What does everyone else think?

 

If you're using a flash to scale for the injectors, I don't think 720s are overkill. I'd hate to scale for that size injector using just an SAFC. That would be some mad retarded timing.

With a Buschur Stage 4 and a BR440 using 680cc injectors, I'm seeing 75-78% duty cycle at redline and 20 psi, running AFRs i nthe 11.0-11.2 range. I'd like to try some water injection and crank the boost up to 24 or 25 psi on 93 octane. I bet the injector duty cycles would be in the low 90s at that level of boost,

 

25psi on race gas, Tommi Makinen turbo, SSautochrome manifold, turbo-back exhaust, 264/264 cams, cam gears, AMS FMIC and lower IC pipe, all on stock injectors. Tuned with an XEDE to 320whp on a Dyno Dynamics.

 

Why such low #'s

 

Dyno Dynamics dyno. For Dynojet numbers, multiply by 1.15: (320*1.15) = ~368whp

 

At what RPM do you hit 100% duty cycle?

Basically when you're hitting 90% and up you're just spraying the backs of the valves with fuel. This fuel atomizes anyway when the valve opens but it's not ideal.

 

The car never hit 100% IDCs or maxes the injectors out. My boost tapers to 18psi by fuel cut. Peak power is just a breath before redline.

 

Sounds like a nice tune. AFRs? Running lean?

 

Clean as a whistle; Shiv tuned it again last weekend. ~11.6 tapering to 11.2 on pump and ~12.4 tapering to 11.8 on race gas with lots more timing. No knock in sight.

 

and when something running close to max hiccups and you puke your motor you will be glad you saved the $400.00 to pay for the rebuild ...I'm biased as my car can see 30+ seconds at full boost and 8,000+on the rev counter...bigger injectors = CHEAP insurance

 

So your saying pay the $400 and get larger injectors just to be safe. I agree, but funds are limited. What size would you go with for my set up?

 

Buschurs first step is to 680cc that gives you room to mod to about 400 whp with lower than 90% IDC if funds are limited getting past 400 WHP should give you lots of time on your 680's

 

Robi, could you kindly explain what these possible "hiccups" are and if/how they (the "hiccups") are more likely to happen to OE injectors than aftermarket replacements?

shiv